Bluetooth to cell phone makes sense, but where can I find out details for that? I have a simple cell phone that does do bluetooth, yes, and I can probably figure out how to pair the two up, but I'm not sure where to go from there.

USB modem also sounds good. I'm assuming a converter would convert a regular USB connection to the USB micro connection on the N810. What I'm thinking about in this respect is something that would be a USB "radio modem" via Verizon or something. Have folks used that?